The present invention relates generally to a transfer mechanism for use with live roller line shaft conveyors and, more particularly, to an improved bi-directional transfer mechanism which is driven by the drive shaft of a live roller conveyor.
Bi-directional transfer mechanisms for transferring articles from one conveyor pass line to another are well known in the art. In general, conventional devices of the type similar to the present invention utilize one or more conveying members of some type which are supported for rotation transverse to the pass line of the conveyor. These conveying members are typically located between the rollers of the conveyor and are positioned parallel thereto on a support structure capable of vertical movement. In the prior art, the conveying member is driven by a drive system comprising a motor, which is used solely for driving the transfer mechanism, and some type of sprocket or gear system.
In its non-transfer position, the conveying member of the prior art bi-directional transfer mechanisms is positioned below the conveying surface or pass line of the conveyor. When a transfer operation is desired, the support structure is displaced upward until the conveying member is displaced sufficiently above the pass line of the conveyor so as to transfer the desired article. While the support structure is being displaced, the transfer drive motor is energized in the appropriate direction so as to drive the conveying member in the desired direction.
Prior art bi-directional transfer mechanisms of the type described above have been characterized by problems and disadvantages which desirably could be eliminated. For example, these transfer mechanisms require motors which are solely dedicated to driving the transfer mechanism. The present invention eliminates the need for additional motors because the conveying members are driven by the conveyor drive shaft, which is always rotating while the live roller conveyor is in operation. By eliminating the transfer drive motor, the conveyor system and transfer mechanisms require less maintenance. Additionally, because the transfer mechanism does not use its own motor, there is less likelihood that an entire conveyor system will have to be shut down or modified because a transfer mechanism is not working properly.
Likewise, in order to transfer articles in more than one direction, prior art transfer mechanisms reversed the movement of the conveying member and thus required a more sophisticated control system than that of the present invention. In order to reverse the movement of the conveying member, prior art control systems had to change the direction of rotation of the motor or use some other means to change the direction of rotation of the conveying member. As a result, the control system not only had to control the vertical displacement of the support structure, but also control the direction of rotation of the conveying member. In the present system, because the direction of article transfer is controlled by the vertical displacement of the lift tables, the control system must only control the vertical displacement of the lift tables. Thus, a less sophisticated and thus less expensive control system may be utilized.
The present invention operates to overcome the foregoing problems and disadvantages by providing a bi-directional transfer mechanism is which the endless conveying member is driven by the conveyor drive shaft and conveyor drive motor. The conveying member is rotatably mounted on guide means located on first and second vertically displaceable lift tables. The conveying member is reeved around the guide means and the conveyor drive shaft such that it is driven in one direction on the guide means of the first lift table and driven in the opposite direction on the guide means of the second lift table. Lift means for selectively displacing the first and second lift tables between a transfer position and a non-transfer position is also provided. In the transfer position, the lift table guide means is displaced such that the endless conveying member is raised above the conveying surface of the conveyor. In the non-transfer idle position, the lift table guide means is displaced such that the endless conveying member is positioned below the conveying surface. By selectively displacing the desired lift table, transfer of articles in two desired directions can be effected.
It is, therefore, a general object of the present invention to provide a bi-directional transfer mechanism having an improved drive system.
Another object of the present invention is to provide a bi-directional transfer mechanism of the type in which the conveying member is driven by the conveyor line shaft and conveyor drive motor.
A further object of the present invention is to provide a bi-directional transfer mechanism of the type in which the conveying member is reeved around guide means mounted on first and second lift tables such that the conveying member is driven in one direction on the guide means of the first lift table and is driven in the opposite direction on the guide means of the second lift table during the operation of the conveyor.
These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.